Patriot defense holding its own

The Patriot defense has, for the most part, proven to be stouter than Guinness.

The unit ranks second in points allowed, which is coach Bill Belichick’s preferred way to rate a defense, and sixth in yards allowed, which is how the NFL ranks its defenses.

The Patriots, who host the Lions Sunday, have surrendered 144 points at an average of 13.1 a game. Only the vaunted Bears are better at 137 and 12.5.

Chicago leads the league in total defense, yielding 261.1 yards a game. Baltimore, Jacksonville, Dallas and Miami also check in ahead of the Patriots (286.8).

The New Englanders are formidable, but there is, as Belichick is fond to say, always room for improvement.

That’s certainly the case when it comes to holding their ground on third down. If it seems like the defense can’t get off the field these days it’s because it can’t.

The Patriots are allowing foes — only two of whom rank in the top 10 in third-down efficiency — to convert at a steady clip of 37.2 percent. That places them in a tie for 14th overall.

Those are average numbers and Belichick equated them with average play. “If that’s what the numbers are, I can’t argue with those,” he said.

This isn’t a new story, but rather one that’s getting old and problematic.

In the last month, the Colts made good on 50 percent of their third-down opportunities, the Jets 46.2 percent and the Bears 43.8. The only break came against a Packers team (1 for 13, 7.7 percent) that was so dreadful it couldn’t have converted an aluminum can into five cents.

“I’d like for us to be at the top of the league on third-down defense,” Belichick said of the spot currently occupied by the Bears. “That means we’re getting off the field quicker and turning the ball over to the offense and having better field position.

“There’s certainly room for improvement there and the longer the yardage the more you’d like to think that you could stop them in those situations. Sometimes we have. Sometimes we haven’t.”

The Patriots have regularly found themselves in long — and supposedly advantageous — third-down situations because they surrender just 4.5 yards on first down. Only two teams are better in that regard.

What they haven’t been able to do is quickly close out a series, teams routinely springing receivers for big gains and a new set of downs.

The Bears faced third and (at least) 7 yards on nine occasions. They passed every time, coming up with five first downs (three via receptions, two on penalties in the secondary).

A rash of injuries to the defensive backs — there hasn’t been a dime package for weeks and receiver Troy Brown is the nickel back — hasn’t helped matters. Nor have injuries to linemen extraordinaire Richard Seymour and Ty Warren.

The situation is delicate enough that affable Artrell Hawkins, who said he had a minute for one final question yesterday, quickly took the fifth when asked what the trouble was on the third.

“I’m not going to talk about that,” Hawkins said with a laugh, certain he had just avoided a trap of some sort. “I don’t have enough time to get into it. I don’t want to say the wrong thing in a hurry.”

What has gone right for the defense is its ability to step up as it gets backed up to the goal line.

“There are times when we have had people who have driven the ball on us and we’ve played well in the red zone,” linebacker Mike Vrabel said. “If we’re not very good on third down, you better be pretty good in the red zone because third-down conversions lead to red-zone opportunities.”

The Patriots check in third in that department, having given up eight touchdowns in 21 trips (38.1 percent) inside the 20.

Other than Roy Williams, the Detroit offense hasn’t been effective. They are tied for 30th with a success — that’s a loose interpretation of the word — rate of 31 percent on third down.

Still, it should make for any interesting afternoon.

“Most teams you can play a little bit of their down and distance tendencies, but not with Mike (Martz),” Belichick said of the Lions’ unpredictable offensive coordinator. “Third-and-18, it doesn’t bother them. … They throw 20-yard in-cuts and hit them. They run 20-yard seam routes. Slim post. They don’t care.”

The New Englanders have an overall defense that’s as strong as any in the NFL, but with the playoffs on the horizon it would behoove them to start displaying some of that stoutness on third down.